This invention relates to rocket engines in general and, in particular, to a new and useful cover of easily destructible material for closing the air inlet openings into the combustion chamber, in particular of ram jet rocket engines and to a strike or ignition device activated by internally generated pressure for destroying the cover at the end of the launch operation and at the beginning of cruising.
In ram jet rocket engines, there is provided for the launch phase, as described in U.S. Pat. No. 3,901,028, a solid rocket fuel, often in a common combustion chamber. The fuel brings the missile to the high flight velocity required for ram jet operation. The velocity is suitable for making sufficient air quantities available at a sufficient pressure for cruising operation. During the cruising operation, air oxygen and fuel-rich gases produced by a solid fuel are brought to reaction in a combustion chamber. Contiguous to the combustion chamber is a convergent-divergent propelling nozzle which transforms the pressure energy generated in the combustion chamber into outflow or reaction energy. In order to keep the air inlet or inflow openings to the combustion chamber closed during the launch phase, covers of easily breakable material are provided at the openings.
After completion of the launch phase and at the beginning of the cruising phase, the covers are destroyed by outside action, so that the air inflow openings are then free. Due to the available ram pressure of the air, the cover fragments are rearwardly ejected via the combustion chamber and through the propelling nozzle into the surrounding environment. It is possible to disintegrate the cover with a pyrotechnic charge or by a mechanical strike device by means of a pretensioned spring.
A special problem resides in eliminating the covers at the right time and, above all, disintegrating them into minute pieces, in order to protect the missile or the internal systems of the engine, respectively, while not endangering other missiles possibly flying along in formation therewith.